1.School of Nuclear Science and Technology, University of South China,Hengyang,Hunan 421001,China
2. National Institute of Metrology,Beijing 100029,China
Abstract：Based on the calibration method in the IAEA TRS 457 report, RQT 8 radiation quality was established. The spectra and angular distributions for RQT 8 radiation quality was performed by Monte Carlo simulation software EGSnrc with the distance of 95 cm, radius of 5 cm between tube focal spot and recording planar, which constructing the model of CT chambers calibration field. The effection of calibration CT chambers was studied under additional aperture with different length as well as angle edges. The result shows that the deviation of established Half-value Layer for reference radiation quality no more than 1.4%, the scattering and transmission is the least when the width of additional apertures is 50mm and the opening angle is 80°, all of which is reaching on the requirements of calibration, testing and international comparison for CT chambers.
［1］樊成,张辉,郭彬. CT剂量计的校准［J］. 中国计量,2009,(7):77-78.
［2］尉可道. CT剂量的测量及其表达［J］. 中华放射医学与防护杂志,1997,(5):347-351.
［3］Nickoloff E L, Alderson P O. Radiation exposure to patients from CT: reality, public perception, and policy［J］. Am J Roentgenol, 2001, 177(2): 285-287.
［4］Geleijns J, van Unnik J G, Zoetelief J, et al. Comparison of two methods for assessing patient dose from computed tomography［J］. Br J Radiol, 1994, 67(796): 360-365.
［5］IAEA. Dosimetry in Diagnostic Radiology: An International Code of Practice［R］. IAEA Technical Reports Series No.457, 1996.
［6］段小娟. 低能X射线空气比释动能标准辐射场能谱的测量与研究［D］.成都:成都理工大学,2012.
［7］郭彬,樊成.诊断X射线辐射质RQR系列建立方法研究［J］.计量学报,2011,32(6A):45-47.
［8］葛双,吴金杰,邱小平,等.工业钼靶X射线光机能谱的蒙特卡罗模拟［J］. 计量学报,2015,36(6):647-651.
［9］陈成,吴金杰,周四春,等. CT技术结合MC模拟探测器效率刻度曲线［J］. 核电子学与探测技术,2015,(5):490-494.
［10］IEC. Medical diagnostic X-ray equipment Radiation conditions for use in the determination of characteristics: IEC 61267:2005［S］. 2005.
2016, Vol. 37 
